Flood Risk Assessment in Herefordshire

Our team at Unda use years of experience to prepare comprehensive flood risk assessments and drainage strategies for commercial and residential sites across Herefordshire. A flood risk assessment in Herefordshire shows your local planning authority that a development will stay safe from flooding for its whole lifetime, without pushing flood risk onto land downstream.

Herefordshire is shaped by the River Wye and the River Lugg. Both rivers gather their water in the Welsh hills and arrive in the county already carrying the runoff from a wide upland catchment, so a wet week over mid-Wales becomes a flood peak in Hereford and Leominster soon after. We assess every source that matters here, from the Wye and Lugg and their tributaries to the surface water that overwhelms the drains in the market towns and the groundwater that rises through the river gravels, then deal directly with the Environment Agency and Herefordshire Council on your behalf. We guide architects, planning consultants, developers, landowners, home buyers and businesses through to a decision, whether the report is needed for planning, a property purchase, a mortgage or insurance, BREEAM, or a surface-water drainage strategy.

If you need a quote or want to talk a site through, contact one of our experienced flood risk consultants on 01293 214444.

In February 2020 the Wye at Hereford reached its highest level in more than 200 years, and the Lugg broke its record too. That is the benchmark a flood risk assessment in Herefordshire has to be built around: the river, the surface water and the groundwater read together against the real, recorded history of the county.

Flood risk assessment in Herefordshire at a glance

• Two rivers set the pattern. The Wye runs through Hereford and Ross-on-Wye, the Lugg through Leominster, and both rise in Wales, so much of the flood risk here is decided upstream and arrives fast.
• February 2020 reset the record. Over the weekend of 15–16 February 2020 the Wye and the Lugg exceeded their highest recorded levels, around 48 properties flooded at Hampton Bishop alone, and residents were evacuated from parts of Hereford.
• Herefordshire Council is your Lead Local Flood Authority. As a unitary authority it leads on surface water, groundwater and ordinary watercourses, while the Environment Agency leads on the Wye and the Lugg.
• Phosphate rules shape drainage here. Much of the county drains to the Lugg and Wye Special Areas of Conservation, so a development's drainage strategy is tied to nutrient neutrality in a way that is unusual nationally.

Check flood risk anywhere in Herefordshire

Herefordshire is outlined below. Screen any postcode in the county against Environment Agency data for rivers and sea, surface water and the planning flood zones, with a climate outlook to 2125. It is an indicative first pass, not a substitute for a site-specific assessment.

Flood risk in Herefordshire: the Wye, the Lugg and surface water

River flooding dominates Herefordshire. The Wye and the Lugg drain most of the county, and because both rise in the Welsh uplands they respond quickly to heavy rain far from the sites they threaten. Surface water now overwhelms the drains in Hereford, Leominster, Ross-on-Wye and Ledbury, and groundwater rises through the river gravels and the clay-rich valley deposits, so most sites here face more than one source at once.

The Wye rises on Plynlimon in mid-Wales and flows through Hereford and Ross-on-Wye before leaving the county towards Monmouth and the Severn estuary. The Lugg, its largest tributary, contributes around a fifth of the Wye's flow, rises in Radnorshire and runs south through Leominster, gathering the Arrow from Kington and the Frome from Bromyard before it joins the Wye below Mordiford. Working out which watercourse drives the risk on a given site, and how quickly it rises, is the heart of a credible flood risk assessment.

• Rivers (fluvial). The Wye and the Lugg, with the Arrow, Frome and Monnow, flood the valley floors through Hereford, Leominster, Ross-on-Wye and the surrounding villages. Land in Flood Zones 2 and 3 along these corridors almost always needs an assessment.
• Surface water (pluvial). Now the most widespread flood risk in England. Intense rain overwhelms the drains in the market towns, as Ledbury found in July 2007. Since the 2025 Planning Practice Guidance update, surface water on the Flood Map for Planning can trigger an assessment even on a Flood Zone 1 site.
• Groundwater. The sands and gravels of the Wye and Lugg valleys, and the clay-rich glacial till across the county, can raise water tables that flood low ground and basements without showing on a river map. This matters for any soakaway or below-ground level — see groundwater flood risk.
• Sewers and ordinary watercourses. Smaller brooks and the surface-water sewers back up in heavy rain. This is Herefordshire Council's responsibility as Lead Local Flood Authority rather than the Environment Agency's — see the role the LLFA plays.

Hereford shows why a single map is never enough. The Wye floodplain runs against Belmont, Hunderton and the low ground at Hampton Bishop and Mordiford, where the Lugg meets the Wye, while parts of the city flood from surface water that has nowhere to drain by gravity. A scheme there has to reconcile both. Our notes on whether flood maps are accurate and on critical drainage areas set out how these sources interact on the ground.

A history of flooding in Herefordshire

These dated events are why the council scrutinises development so closely, and why a flood risk assessment in Herefordshire has to be evidence-led rather than generic. Each one is recorded data a regulator will expect your report to account for.

• February 2020 — the record floods. Over the weekend of 15–16 February 2020, on the back of Storm Ciara and Storm Dennis, the Wye at Hereford reached about 6.1 metres, its highest in more than 200 years, and the Lugg exceeded its highest recorded level. The Environment Agency called the levels exceptional.
• Hampton Bishop and the Lugg. Around 48 properties flooded or were affected at Hampton Bishop in February 2020, while the embankment defences there protected roughly 150 more. Residents were evacuated from the Hinton and Putson areas of Hereford, and the Lugg flood embankment later needed repair.
• July 2007 — surface water in Ledbury. Intense summer rain overwhelmed the drainage in Ledbury, flooding Church Street, Newbury Park Road and parts of Lower Road and Little Marcle Road — a reminder that the risk here is not only the main rivers.
• Recent winters. Storm Bert in November 2024 brought further high flows and flash flooding across the Wye and Lugg catchments, keeping flood resilience high on the agenda for the county's communities.

A pattern runs through all of it: ground that flooded once tends to flood again. A robust assessment treats this recorded history as evidence, not background colour.

Planning policy and your Lead Local Flood Authority in Herefordshire

Two kinds of authority set the rules. The Environment Agency leads on the Wye and the Lugg and the county's other main rivers. Herefordshire Council, as a unitary authority, is the Lead Local Flood Authority (LLFA) for surface water, groundwater and ordinary watercourses, and is also the local planning authority that decides your application.

A developer here deals with Herefordshire Council in two roles at once, alongside the Environment Agency and, where it shares the headwaters, an awareness that the rivers arrive from Wales. The council's Local Flood Risk Management Strategy and its Strategic Flood Risk Assessment set the local evidence base, and the LLFA is a statutory consultee on surface water drainage for major development — see the role the LLFA plays and how an LLFA drainage objection can hold an application up.

Your assessment and drainage strategy must satisfy national policy, set out in the NPPF and its Planning Practice Guidance, and the local framework: the council's Local Flood Risk Management Strategy, its Strategic Flood Risk Assessment and the Local Plan Core Strategy, where Policy SD3 requires sustainable water management as an integral part of new development. Where a higher-risk site is involved, the Sequential and Exception Tests apply. On drainage, the four pillars of SuDS and the critical drainage picture shape what the council will accept, with surface water designed so there is no flooding in the 1-in-30-year storm and no increased risk in the 1-in-100-year storm once a climate change allowance is added.

What your flood risk assessment in Herefordshire must show

• Risk assessed from every credible source, using the Flood Map for Planning and local data.
• An appropriate location, tested against the Sequential Test where policy requires it.
• Safe for its lifetime, once the Environment Agency climate change allowances are applied.
• No increase in flood risk elsewhere, with attenuation and, where needed, compensatory storage.
• Residual risk managed, with safe access, egress and finished floor levels, sometimes through floodable voids on constrained riverside sites.

Phosphate and nutrient neutrality: what the Lugg and Wye rules mean for your drainage

Across much of Herefordshire, a development's drainage strategy is tied to river water quality in a way that is unusual nationally. Because the River Lugg and River Wye Special Areas of Conservation are failing their conservation targets for phosphate, new development that adds foul or surface water to these catchments has to demonstrate nutrient neutrality before it can be permitted.

Following Natural England advice in 2019, Herefordshire Council concluded it could not grant permission for development in the Lugg catchment, which takes in the Frome and Arrow, unless it could show no net increase in phosphate reaching the protected rivers. Hundreds of applications, amounting to more than 2,000 homes, were held up while a mitigation route was found. The council's response included the Luston Wetland, which captures phosphate and generates credits developers can buy to offset their scheme. For most applicants this sits alongside the flood and drainage work rather than replacing it: the way surface water is managed, where foul drainage discharges, and whether a site relies on a septic system all feed into the nutrient calculation.

• Nutrient neutrality applies to the Lugg and Wye catchments. Development must show it will not add phosphate to the protected rivers, assessed with Natural England's nutrient budget calculator. See Herefordshire Council's guidance for the Lugg catchment.
• Foul drainage is part of the picture. On unsewered sites the choice between a package treatment plant, a drainage field and a mains connection affects both the phosphate budget and compliance with the General Binding Rules for small sewage discharges.
• Surface water design helps. Sustainable drainage that slows, stores and treats runoff supports water quality as well as flood risk, which is why an early, joined-up drainage strategy is worth more here than almost anywhere.

Development and flood risk assessment in Herefordshire

Herefordshire is a rural county of market towns and farmland, and the kind of site you bring forward shapes the assessment you need. The right scope is the difference between a clean approval and a drainage or flood objection that holds an application up for months.

• Market-town housing. Edge-of-settlement and infill schemes at Hereford, Leominster, Ross-on-Wye and Ledbury frequently sit near the Wye, Lugg or an ordinary watercourse, needing finished floor levels, safe access and egress and a surface-water strategy that satisfies the council.
• Riverside and city-centre regeneration. Redevelopment along the Wye through Hereford often falls in Flood Zones 2 and 3, where residual risk and compensatory storage decide whether a scheme is safe.
• Agricultural and rural conversions. Barn conversions and rural new builds across the county usually turn on surface water, infiltration and ordinary watercourses rather than a main river, and on the right preliminary drainage design before the layout is fixed.
• Sites relying on soakaways. On the clay-rich tills that cover much of the county, infiltration often fails, so infiltration testing to BRE 365 is needed before a drainage strategy assumes a soakaway will work.

Climate change is not optional here. A Herefordshire assessment must apply the Environment Agency's allowances for higher river flows and rainfall over the development's lifetime, generally 100 years for housing, which sets floor levels, freeboard and how much attenuation a drainage scheme needs.

Home buyers and businesses come to us too. A flood risk question can affect a purchase and house prices, and a conveyancing search is not the same thing as a planning-grade assessment. Knowing which you actually need saves time and money, and our guide on doing your own assessment explains where the line falls.

How Unda helps with flood risk assessment in Herefordshire

We act as the accurate translation layer between your scheme and the requirements set by the Environment Agency, Herefordshire Council and national planning policy. We are experts on the county's flooding, not a generic report mill.

A flood risk assessment in Herefordshire from Unda assesses every credible source, from the Wye and Lugg to surface water, groundwater and any ordinary watercourse on the boundary, compares modelled flood levels against your proposed floor levels, sets safe access and egress, and recommends mitigation the regulators will accept. We are a CIWEM Business Partner with chartered members, and a senior consultant signs off every report. Where the council needs it, a surface-water drainage strategy sits alongside the assessment as a separate report, so the two cases stay consistent and an objection has nowhere to land.

Flood risk assessments and related reports for every situation in Herefordshire

A flood risk assessment, a Sequential or Exception Test and a drainage strategy are three distinct reports. They often travel together in a planning submission, but they answer different questions: is the site safe, should the development be here, and where does the surface water go. We prepare all three, alongside the right form of assessment for buyers, lenders and BREEAM.

Flood risk assessments

• Flood risk assessment for planning. The core report, site-specific and prepared to satisfy the NPPF, the Environment Agency and Herefordshire Council. Groundwater and, where needed, flood modelling are assessed within it rather than as separate reports.
• Homebuyer and property-purchase survey. For conveyancing, where a search has flagged Wye or Lugg valley risk and you need the actual building assessed, not a broad map.
• Flood risk assessment for insurance. Property-specific evidence for brokers and underwriters where premiums have risen or cover has been restricted.
• Flood risk assessment for BREEAM. Structured around BREEAM Pol 03, which is credit-driven rather than safety-driven, so a planning assessment alone rarely satisfies it.
• Groundwater flood risk. A defensible design water table for Wye and Lugg valley sites and any basement, assessed as a source within the assessment, or as a standalone hydrogeological study on complex sites.

Sequential and Exception Tests

The Sequential and Exception Tests are a separate, locational report about whether a development should be in a higher-risk location at all. The Sequential Test defines an area of search, identifies reasonably available lower-risk sites and justifies the proposed site; the Exception Test is the second gate where development still needs to proceed. A clean site-specific assessment showing the development is not actually within an area at risk can remove the need at application stage — a live policy area, as our note on the Yatton judgment explains.

Drainage strategy and SuDS

• Sustainable drainage strategy (SuDS). Surface-water engineering that calculates existing versus proposed runoff and proposes SuDS to hold discharge within the council's standards and support river water quality.
• Preliminary drainage design. The early, outline read that flags infiltration issues before they affect layout and land value.
• Discharge of drainage conditions. The detailed stage to discharge a pre-commencement or pre-occupation drainage condition.
• Flood modelling. 1D and 2D hydraulic modelling, a technique that feeds the assessment, Sequential Test or drainage design where national mapping is not enough.

Early in a drainage strategy it helps to know whether the ground will take water: our free geology and ground conditions map and BRE 365 infiltration rate calculator give an indicative read before a trial pit, and the drainage calculators help size the scheme. You can screen a postcode on our flood risk map, and every report is overseen by a chartered flood risk consultant who stays involved past the report to answer objections. You can read more about Unda and our work in the media.

Herefordshire flood resources and contacts

The most reliable Herefordshire flood information comes from the lead authorities. For an immediate threat to life during a flood, always call 999; for a power cut during flooding, call 105.

• Check for flooding in Herefordshire. Environment Agency live warnings, river levels and maps at check-for-flooding.service.gov.uk; sign up for flood warnings or call Floodline on 0345 988 1188.
• Herefordshire Council flood risk. Report flooding, strategy and developer guidance at Herefordshire Council, the Lead Local Flood Authority for surface water, groundwater and ordinary watercourses.
• Nutrient management. Phosphate and nutrient-neutrality guidance for the Lugg and Wye catchments at Herefordshire Council.
• English Severn and Wye Regional Flood and Coastal Committee. Regional investment and priorities via the English Severn and Wye RFCC.
• Live river levels. Whether the Wye or the Lugg are running high right now via our live river levels map.

For flooding from blocked or burst sewers, contact your water company — Welsh Water serves most of Herefordshire, including Hereford, while Severn Trent serves parts of the east. For broader policy context, our notes on the Environment Agency's planning role and on riparian ownership are a good starting point for anyone with a watercourse on their land.

Flood risk assessment in Herefordshire: frequently asked questions